In the railroad industry, electrical energy is supplied for individual railroad cars, such as a caboose, by employing the rotational energy derived from a rotating shaft such as a rotating axle. The most common method of transmitting this rotational energy is to use "V"-Belts and pulleys in various ways. The transmitted rotational energy is then used to produce the necessary mechanical power that drives a variety of machinery such as electrical generating equipment (i.e., generators or alternators).
However, this system of transmitting the rotational energy transmission is not without problems. For example, the "V"-Belts attached to the rotating axle are often required to operate in an environment that is exposed to a number of hazards, including the elements. Thus, while the railroad vehicle is traveling cross-country, the rotating axle is often exposed to dirt, grit, rocks, sticks, and the like, thrown up the moving vehicle. In addition, railroad vehicles often traverse substantial distances in short amounts of time and, accordingly, are subjected to, and in turn subject these "V"-belts to, large temperature variations. All this greatly increases the wear imposed upon the "V"-belts energy transmission system. In turn, the rotational energy transmission system often requires part replacement and/or adjustments necessitated by such wear.
When a belt breaks or becomes unusable due to wear, replacement is a time consuming and expensive operation; an operation that must be performed in a railroad yard equipped to separate the axle, to which the system (i.e., the "V"-belts) is coupled, from the railroad car in order to replace damaged or broken belt or belts.
In addition, recent increases in electrical requirements of many railroad cars have been limited by the torque requirements of high capacity generators or alternators. The torque transmitting capabilities of "V"-belt systems cannot drive such high capacity equipment efficiently. One attempted solution is to use two or more "V"-belts where, before, only one was used. However, that this solution is negligible because one belt usually wears or stretches more than the other or others, the end result being that only one belt actually performs the rotational energy transmitting function.
What the railroad industry presently does is to use low torque generators or alternators that are designed to produce the required electrical energy by operating at high revolutions-per-minute (RPM) in order to not exceed the torque transmitting capabilities of "V"-belted transmission systems. This requires, however, that one particular "V"-belt transmission system be used when the vehicle is operated at high rates of speed, such as on a cross-country trip, and another particular "V"-belt transmission system in order to continue to operate the generator or alternator at a sufficiently high RPM, while the vehicle travels at a low rate of speed, such as while being used in a freight yard. The change from one system to another usually involves changing and adding "V"-belts and pulleys, again a time-consuming and expensive chore.
It can be seen, therefore, that there exists a need for electrical generating equipment of sufficiently high capacity that can be employed by a vehicle having a rotating axle for driving the electrical equipment. Preferably, the electrical equipment will be coupled to the rotating axle in a manner that allows sufficient torque to be developed to operate the equipment at all reasonable vehicle speeds, yet allow the generator to be easily replaced. In addition, the method of coupling the generator to the rotating axle should not require extensive modification of the axle or its associated parts.